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Section 2 Measuring Earthquakes

Vocabulary

focus- the place in earth's crust where rock breaks
epicenter- something that is on the surface above the focus
seismic waves- vibrations that are traveling though out the earth releasing energy during an earthquake
p waves- first earthquake waves
s waves- second earthquake waves, after the p waves
surface waves- the waves that moves the slowest but has the strongest shaking
seismograph- a machine that records the shaking made by a seismic waves
magnitude- the way of measuring how strong an earthquake is
mercalli scale- a scale made to measure earthquake by looking at how strong the damage was
richter scale- a scale rating how big the seismic waves are
moment magnitude scale- a scale that guesses how much energy is let out

outline

Intoduction

Siesmic Waves

• Primary Waves which are also called P waves
• Secondary Wave which are also called S waves
• Surface Waves

Detecting Siesmic Waves

Measuring Earhquakes

• Mercalli Scale
• Richter Scale
• Moment Magnitude Scale

Locating The Epicenter

• Scientists draw three circles to find the epicenter